ATLANTA - Before anyone hit a shot Thursday in the first round of the season-ending Tour Championship, Xander Schauffele was six shots in back of the leader.

By day's end, he had a share of the lead.

Such is life in the new FedExCup Playoffs, where a unique, staggered scoring format was created to simplify matters and stifle confusion at the final event of the playoffs. Chalkboards and an understanding of algorithms are no longer needed as the players' starting score was determined by his position in the FedExCup standings heading into the Tour Championship.

Thus, Justin Thomas, a winner last week in the BMW Championship, began the tournament at 10 under. Patrick Cantlay, second in the standings, was at 8 under, world No. 1 Brooks Koepka at 7 under and so forth all the way to those 26th through 30th players starting 10 shots back at even par.

Well, Schauffele made up the six shots he spotted Thomas with a 6-under-par 64 at East Lake to get to 10 under. He shares the lead with Thomas, who shot 70, and Brooks Koepka, whose nude portraits in the ESPN The Magazine Body Issue went viral Wednesday night. Koepka was his usual forceful self and shot 67 despite tussling with too much of the Bermuda rough and with too many bunkers.

Rory McIlroy, the 2016 FedExCup and Tour Championship winner, was one shot back after a 66. Matt Kuchar moved into a share of fifth with a 66, while Cantlay fell into a share of fifth with a 70.

On the other end of the leaderboard, Lucas Glover shot 73 and is 13 shots back.

Schauffele joked that he had a putt for 59 on the final hole, seeing as the scoreboard had him at 10 under. But he started at 4 under and just kept his head down for the most part in hopes of not getting wrapped up in the scoring structure.

"It is what it is," said Schauffele, who won twice earlier this year. "I mean, that's how I'm taking it. I think everyone needed help from J.T. If J.T. went out and shot a pair of 65s, I don't think the Tour would be very happy and I don't think the rest of the field would be happy. But it looks to be a good tournament so far."

It could be a repeat of 2017, when Schauffele battled Thomas on the final day, with Schauffele winning the Tour Championship and Thomas the FedExCup. Thomas is still irked that he didn't pull off the double, as he lost the Tour Championship by one.

But in another change this year, there no longer will be an awkward scene where two winners are given hardware, as was the case last year when Tiger Woods' victory in The Tour Championship overshadowed Justin Rose winning the FedExCup, and the previous year with Thomas and Schauffele.

"It's just Thursday," Schauffele said. "I'd love to be a thorn in someone's side on Sunday."

Koepka, the only three-time winner this season, including his fourth major championship title at the PGA Championship, said he found something on the back nine that led him to three birdies in the last four holes.

"I played it like a five-day event and I was three down," Koepka said. "So it's nice to be tied for the lead after the first day."

Paul Casey didn't know what to make of the first day, especially starting eight shots back before hitting a golf ball. But he moved into a tie for eighth, four shots back, after a 66.

"It didn't feel like a normal start," Casey said. "It was a little bit strange. After five holes, I wanted to see scores. I never usually care about what's going on after five holes. Because if (Thomas) came out with five straight birdies, it would be like, 'OK, we're done.' But we've got a golf event now.